A small biotech is worth more than four times what it was last week, thanks to a capsule filled with spores.
On Monday, Seres Therapeutics became the first company to detail positive results from a pivotal study of a microbiome drug. The study looked at 182 patients with recurring infections from a bacterium called C. difficile, and found those who took Seres' capsule were significantly less likely to see their infections return. In fact, after eight weeks, nearly 90% of patients on the drug were without C. diff infections, versus almost 60% of the placebo group.
Seres said the results provide enough support to submit its capsule, known as SER-109, for approval, putting the company in position to win the first-ever regulatory clearance for a microbiome-based drug. The company plans to meet with the Food and Drug Administration soon to discuss next steps, but anticipates a regulatory filing will come next year.
"Microbiome therapeutics are not a distant future promise, but a very real and very promising treatment modality that is here, now," Seres CEO Eric Shaff said on a call with investors. The company's share price surpassed $20 Monday morning, up 350% from its $4.64 close on Friday.
Two months ago in June, Finch Therapeutics also reported success from a study of a microbiome-targeting drug in patients fighting recurrent C. diff infections. The company expects to run a second trial to confirm the results before submitting its therapy to the FDA.
Rebiotix, another developer in the space, said in May a Phase 3 trial of its C. difficile therapy succeeded, but released no actual data.
The term microbiome refers to the wide assortment of bacteria, fungi and viruses that live inside humans. Over the last decade, drugmakers have made more concentrated efforts to harness these microbe communities to fight disease, with Seres being one of the pioneers in that work.
The company suffered a major setback in 2016, though, when SER-109 missed the main goal of a smaller C. diff study. Seres appeared to chalk the failure up to patient screening issues, and chose to move forward with a large trial that would use the "gold standard" for detecting C. diff infections.
That choice has now generated results which may land Seres its first approved product. Chief Medical Officer Lisa von Moltke noted how the efficacy data "substantially exceeded" the benchmarks the FDA wanted to see for a single, pivotal study. Specifically, she said the agency had indicated the relative risk for SER-109 — meaning the ratio of infection recurrence between the drug and placebo groups — should be no more than 0.83. It ended up being much lower, at 0.28.
Seres' capsule was also well-tolerated. No patient experienced any treatment-related serious adverse events, and the overall incidence of adverse events was similar between SER-109 and placebo groups. The most common adverse events were flatulence, abdominal distention and abdominal pain, which were generally mild to moderate in nature.
While Seres believes the available results are enough to file for approval, the company acknowledged the FDA could ask for data on more patients, to align with prior guidance that data from around 300 patients on the same dose would be needed to get the drug to market. Von Moltke said a safety database currently has information on roughly 105 patients treated with the SER-109 dose used in pivotal testing. By the time Seres expects to file for approval, "many additional subjects" will be added to the database through an open-label portion of the large trial.
Seres noted, too, how recent challenges with the largest U.S. provider of fecal microbiota transplantations — currently the main treatment used to restore sick microbiomes — should lead to faster enrollment in the open-label study.
As Seres gears up for a critical year in 2021, it's already preparing to commercialize.
The biotech appointed Terri Young, formerly an executive at Sage Therapeutics, to the role of chief commercial and strategy officer in June. On Monday's investor call, Young said she's been focused on recruiting talent to support that side of the business. Shaff said Seres has commercial-scale manufacturing in place.
On price, Shaff didn't provide specifics but said that SER-109's would reflect its innovation and potential savings to the broader healthcare system, given that C. diff is the leading cause of hospital acquired infections. According to research cited by Seres, there are over 450,000 primary C. diff infections in the U.S. each year and about 170,000 recurrent cases, representing an approximately $5 billion annual healthcare burden.
Seres' drug uses spores from a common type of gut bacteria to improve microbiome health.